Firefox 45.6 has high CPU usage with multiple tabs open?

saturnalia0 · Tux's lil' helper Joined: 13 Oct 2016 Posts: 136

Hi. I noticed since the last update Firefox would sporadically have a constant high CPU usage when having multiple tabs opened. I only noticed it because my CPU has heating issues (long story) and after some time of constant CPU usage it beeps because of the high temperature it reaches. Otherwise it's hardly noticeable, CPU usage stays on ~120% according to htop (4 cores, so 400% would mean 100% on all cores). Closing all tabs except one does not solve the issue. Closing all tabs leaving just about:blank opened solves it. I am having troubles reproducing this and could not diagnose if it has something to do with my profile/extensions or not, so I was wondering if anyone else noticed this lately?

[Moderator edit: changed title to reflect Firefox version supplied by OP partway down the thread. -Hu]

Irre · Guru Joined: 09 Nov 2013 Posts: 434 Location: Stockholm

Try www-client/opera

cboldt · Veteran Joined: 24 Aug 2005 Posts: 1046

I had an issue that wasn't high CPU usage, but load average was always about 1.0 with firefox running, and 0.0 without. That funky load average report got cured by using high precision timers in the kernel.

After that, I have had times when firefox would give pretty high CPU usage on occasion - I open with eight tabs. Turned out that the usage was one tab running a video or similar. I noticed the video by accident, troubleshooting by closing one tab at a time, using my (unreliable) intuition about which tab was the most likely offender.

Hu · Administrator Joined: 06 Mar 2007 Posts: 21724

OP: please identify the Firefox versions you have seen affected. Users on ESR currently run 45.x series, whereas users following all the latest Mozilla wackiness run 50.x. Your post might remain relevant long enough that one or both of those series move on to a different number, in which case "latest" could mean something different than it meant when you posted.

saturnalia0 · Tux's lil' helper Joined: 13 Oct 2016 Posts: 136

@cboldt That was my first thought, I ruled that out by doing the same as you did (closing all tabs except one, for every tab opened). The problem is that when I restart Firefox and open the same tabs again, it doesn't always incur in high CPU usage. It's sporadic and I can't seem to debug it.

@Hu www-client/firefox-45.6.0

wvmmhxkh · n00b Joined: 26 Feb 2013 Posts: 5

same thing here both on 50 and 51

Logicien · Posted: Fri Jan 27, 2017 4:01 pm Post subject:

A running Firefox plugin can elevate the cpu usage. Maybe start Firefox in safe mode can tell more precisely what resources Firefox use by itself.

wvmmhxkh · n00b Joined: 26 Feb 2013 Posts: 5